BSS Audio MSR-604ii User manual

BSS Audio MSR-604ii User Manual version v1.4
Page 1
V 1.4 JMK 4th December 1997
MSR-604ii
User Manual
This equipment has been tested and found to comply with the following European
and international Standards for Electromagnetic Compatibility and Electrical Safety:
Radiated Emissions (EU): EN55013 (1990)Associated Equipment
RF Immunity (EU): EN50082/1 (1992)RF Immunity, Fast
Transients ESD
Mains Disturbance (EU): EN61000/3/2 (1995)
Electrical Safety (EU): EN60065 (1993)
IMPORTANT SAFETY INFORMATION
DO NOT REMOVE COVERS. NO USER SERVICEABLE PARTS INSIDE, REFER SERVICING
TO QUALIFIED SERVICE PERSONNEL. THIS EQUIPMENT MUST BE EARTHED.
IT SHOULD NOT BE NECESSARY TO REMOVE ANY PROTECTIVE EARTH OR SIGNAL
CABLE SHIELD CONNECTIONS TO PREVENT GROUND LOOPS. ANY SUCH
DISCONNECTIONS ARE OUTSIDE THE RECOMMENDED PRACTISE OF BSS AUDIO
AND WILL RENDER ANY EMC OR SAFETY CERTIFICATION VOID.
We have written this manual with the aim of helping installers, sound engineers
and consultants alike get to grips with the MSR-604ii and obtain its maximum
capability.
Should you have any comments or questions about applying the MSR-604ii series
within your application, please write to us, or e-mail us, at the addresses in the
warranty section. We welcome any comments or questions regarding the MSR-
604ii series or other BSS products, and you may contact us at the address or World
Wide Web site given in the warranty section.
interstage
Phistersvej 31, 2900 Hellerup, Danmark
Telefon [phone], fax [phone]
www.interstage.dk
-pro audio with a smile

BSS Audio MSR-604ii User Manual version v1.4
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Contents
1 Introduction 3
1.1 MSR-604ii Mic/line signal splitter 3
1.2 MSR-602ii Power supply 4
2 Unpacking 5
3 Connections and control descriptions 5
3.1 AC Power connections and control settings 5
3.2 Voltage setting 7
3.3 Safety earthing 7
3.4 AC Power fusing 7
3.5 DC Power connections 7
3.6 Audio connections 7
4 MSR-602ii Controls 9
5 MSR-604ii Controls 10
6 System implementation and use 11
6.1 Racking 11
6.2 Grounding 12
6.3 Channel coding 13
6.4 Dual power supply operation 13
6.5 Output drive level setting 13
6.6 Multiple output distribution amplifier configuration 14
7 Compatibility with Pre-MkII systems 15
7.1 Installing an MSR-604ii in a MkI system 15
7.2 Installing Pre-MkII MSR-604iis in a new system 16
7.3 Installing a MkII Power supply into a MkI system, and vice versa 16
8 Appendix A 17
8.1 Circuit description 17
9 Service section 18
9.1 Transient suppressor replacement 18
9.2 Input transformer balancing 18
9.3 Output transformer balancing 18
9.4 Setting system jumpers 18
10 Warranty Information 19
11 Specifications 20

BSS Audio MSR-604ii User Manual version v1.4
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1Introduction
It is not uncommon within a sound system which uses microphones as a source of
program, for that microphone to be connected to the input of a number of different
processing facilities.
An example of this would be in sound reinforcement work where a stage
microphone is required to drive the main ‘front of house’ mixing console, the stage
monitoring mixing console, a mobile recording studio and quite possibly an
outside broadcast recording vehicle. It is also common within such a system for the
microphone to be connected to considerable lengths of shielded cable before
being terminated at the processing facilities input connector. Such a load on the
microphone is very much in excess of its design capability, and as a consequence
the level and quality of the sound is impaired.
A further complication can arise within such a system from multiple earthing as
each of the processing facilities would be providing its own ground. To overcome
these problems it is quite common for a multiple winding transformer to be used
which provides separate secondary windings for each of the required outputs. This
solution will solve the multiple grounding problems, however it does not tackle the
sound level and quality problem as, being a passive device, it has no power
amplification capability.
Cost effective active electronic solutions proved elusive until the introduction of
the original BSS MSR-604 overcame the problems of noise and headroom. The
current MSR-604ii further improves upon the performance of the original unit with
yet greater dynamic range, flexibility of gain and level control, internal bus routing,
signal metering and a headphone monitoring facility.
The MSR-604ii is a four channel, four way signal splitting package and the MSR-
602ii is the system power supply capable of supplying power for 40 channels, that
is, 10 separate MSR-604ii units.
1.1 MSR-604ii Mic/line signal splitter
The MSR-604ii has four channels, each of which may be isolated and used totally
independently from the next or, by internal re-configuration, be interconnected to
form distribution amplifier sections with a single input driving up to 64 outputs.
The low noise floor requirement necessitates a remote power supply system, the
MSR-602ii, which provides the required DC voltages.
A MIC/LINE switch introduces a 20dB input pad, which in combination with the 5
step GAIN switch allows any input signal below + 33dBu to be perfectly matched
to the MSR-604iis dynamic range. The setting up process is further assisted by the
provision of a momentary LISTEN switch which routes the signal to a calibrated
HEADROOM meter and a headphone monitor amplifier built into the MSR-602ii
power supply unit. Each channel also has a CLIP LED to give constant warning
against signal overdrive. As a further refinement a separate 10dB input pad may be

BSS Audio MSR-604ii User Manual version v1.4
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activated from the front of house mixing console by switching the desks phantom
supply. This remote attenuator allows the engineer to preserve the channel
headroom directly from the console in the event that an input is overdriven.
Each channel also provides a separate phantom powering selector switch providing
an independent 48V across the ‘mic input’ connector.
Each channel has two low impedance electronically balanced outputs on the rear
panel to feed the MAIN (Front of House) and the MONITOR mixing consoles.
These outputs may be independently configured by internal header blocks to drive
at mic (+3dBu clip) or at line (+23dBu clip) levels. A third setting allows these
outputs to be driven at +13dBu clip which gives a gain/headroom structure
compatible with earlier versions of the MSR-604. The two FEED XLR connectors on
the front panel offer microphone level transformer isolated and balanced outputs.
1.2 MSR-602ii Power supply
The MSR-602ii is the system power supply providing all the necessary DC voltages
for the MSR-604ii. It utilises a custom designed low field toroidal transformer and
separate mu-metal screen to reduce the possibility of mains field coupling into the
electronic circuitry of the MSR-604ii.
The HEADROOM LED meter and high quality headphone amplifier give the
operator absolute confidence in signal integrity during setting up, and provide an
indispensable aid to trouble shooting and fault detection. The signal wiring
involved is contained with the power wiring in a multicore cable for simple
interconnection between units.
In addition it also carries the main system ground switch which has important
considerations within a large system for both safety and noise.
Please read section 6.2; Grounding carefully prior to operating the complete
system.

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2Unpacking
As part of our system of quality control, this product is carefully inspected before
packing to ensure flawless appearance. After unpacking the units, please inspect
for any physical damage and retain the shipping carton and all relevant packing
materials, should the unit require repacking.
In the event that damage has occurred, immediately notify your dealer, so that a
written claim to cover damages can be initiated.
Because this equipment is connected between the microphone and mixing console
or patching system, it is important for safety and system noise that a proper
earthing system is implemented within the cabling system.
Consequently section 6.2; Grounding of this manual should be read prior to
installation and use.
3Connections and control descriptions
3.1 AC Power connections and control settings
Before connecting the MSR-602ii to the AC power source, check that the voltage
selector switch located on the rear panel is correctly set. If a change is necessary,
ensure that the mains fuse is also changed for one of the correct rating. Before
connecting the DC power leads, check that the system ground switch on the rear
panel is also correctly set to ‘earthed’.
The power cord attached to this unit carries the following information label.
WARNING: THIS APPLIANCE MUST BE EARTHED
IMPORTANT: The wires in this mains lead are colour coded in accordance with
the following code.
Green and yellow : Earth
Blue : Neutral
Brown : Live
As the colours of the wires in the mains lead of this appliance may not correspond
with the coloured markings identifying the terminals in your plug, proceed as
follows:
The wire which is coloured green-and-yellow must be connected to the terminal in
the plug which is marked with the letter ‘E’ or by the earth symbol, or coloured
green or green-and-yellow.
The wire which is coloured blue must be connected to the terminal which is
marked with the letter ‘N’ or coloured black.